Process for chemical/thermal treatment without toxic emissions

Abstract

An apparatus and process for chemically and/or thermally treating substances containing or generating toxic substances during treatment is disclosed. Multiple reactors treat the material while the toxic emission containment system separates and cleans the effluents to within acceptable emissions limits as specified by government. The preferred rotary kiln employs a multiple zone reactor system for processing and volumetrically reducing feedstocks. The kiln functions as a primary treatment chamber and contains a rotatable multipurpose admixture and a multiple zone burner system. Induced cyclonic action reduces particulate entrainment, minimizes stratification, and maximizes gas residence time. A direct fed, second stage vitrifying, refining and/or separating furnace yields stabilized products. The preferred process includes an air pollution control system enhanced by a toxic emission containment system which separates the inert effluents from the toxic emissions contained in the treatment process. The toxic emissions are contained, recycled for further treatment or rendered inert. Whenever coolants are inserted directly into the process to lower treatment temperatures, off-gas recycle is used to minimize the quantities to be cleaned. When combustion is an integral part of the thermal treatment process, enriched oxygen is used to displace the nitrogen in the combustion air to reduce the quantities of toxic emissions generated and the quantities of off-gas to be treated downstream of the air pollution control system. Unused admixtures, solid, liquid and gaseous by-products can be isolated.

What is claimed is: 
     
       1. A process for treating feedstock materials to remove contaminants therefrom and to produce a volumetrically reduced, stabilized disposable solid product and/or commercially valuable solid, liquid or gaseous byproducts, said process comprising the steps of: (a) thermally treating said feedstock and oxidizing organic contaminants present in a rotary kiln, and outputting solids, liquids and gases;   (b) vitrifying, refining and separating solids exiting said rotary kiln and outputting said stabilized products and gases;   (c) reacting gases from steps (a) and (b) in a gaseous thermal treat and outputting gases; and,   (d) treating said gases from said step (c) by removing particulate contaminants therefrom and selectively recycling said contaminants to said step (a), (b) or (c).   
     
     
       2. The process as defined in claim 1 wherein said step 1 (d) comprises the treatment steps of: (a) subcooling said gases from said step (1) (d) to remove dirty water therefrom;   (b) passing said subcooled gases from step (a) through an absorption unit to separate carbon dioxide from said recycled contaminants; and,   (c) passing said recycled contaminants from step (b) through a membrane separation system to remove remaining by-product gases from said recycled contaminants.   
     
     
       3. The process as defined in claim 2 wherein said step 2 (b) comprises the further steps of: (a) passing said subcooled gases from step (2) (b) through an absorber operatively coupled to at least one stripper to separate carbon dioxide from said recycled contaminants;   (b) passing said separated carbon dioxide from step (a) through a dense phase membrane to separate industrial grade carbon dioxide from said contaminants; and,   (c) storing and testing said industrial grade carbon dioxide from step (b).   
     
     
       4. The process as defined in claim 2 wherein said step 2 (a) comprises the further step of passing said dirty water through a porous membrane for separating water from said recycled contaminants. 
     
     
       5. The process as defined in claim 2 wherein said membrane separation system comprises a first and second dense phase membrane separation units. 
     
     
       6. The process as defined in claim 1 wherein said step 1 (a) comprises the steps of: passing said feedstocks internally through a generally cylindrical combustion chamber;   rotating said kiln about a longitudinal axis;   thermally treating feedstock tumbling through said chamber with a multiple purpose manifold supported within said treatment chamber substantially parallel to said longitudinal axis, said manifold establishing a plurality of separate, independently operable and longitudinally successive treatment zones for independently inserting admixtures, coolants, recycled flue gases, fuels and oxidants for establishing separate and distinct thermal operating parameters;   fueling said manifold within said plurality of longitudinally successive treatment zones;   delivering oxidizer to said manifold within said plurality of longitudinally successive treatment zones; and,   independently establishing ignition within said zones to activate said rotary kiln.   
     
     
       7. The process as defined in claim 6 including the step of pivoting the multiple purpose manifold about an axis of rotation, and spacing said axis of rotation a selected distance away from said longitudinal axis. 
     
     
       8. The process as defined in claim 7 including the step of providing each of said treatment zones with a plurality of longitudinally spaced apart burners for achieving said thermal parameters, each of said plurality burners defining a plurality of independent, spaced apart tips. 
     
     
       9. The process as defined in claim 6 including the steps of: positioning said multiple purpose manifold a selected distance away from said longitudinal axis of said treatment chamber and above said feedstocks to be thermally treated; and,   directing flame or gases produced by said ignition step substantially perpendicularly away from said multiple purpose manifold and substantially tangential with respect to said cylindrical wall, thereby creating a selected swirling or non-random helical-like gas stream within said treatment chamber.   
     
     
       10. The process as defined in claim 9 including the step of pivoting said multiple purpose manifold about an axis of rotation spaced a selected distance away from said longitudinal axis.